@mixin flex {
  display: flex; /* 新版本语法: Opera 12.1, Firefox 22+ */
  display: -ms-flexbox; /* 混合版本语法: IE 10 */
  display: -webkit-box; /* 老版本语法: Safari, iOS, Android browser, older WebKit browsers. */
  display: -webkit-flex; /* 新版本语法: Chrome 21+ */
}

/* Flex垂直居中 */
@mixin flex-align-center {
  align-items: center;
  -webkit-align-items: center;
  -ms-flex-align: center;
  -webkit-box-align: center;
}

/* 水平居中 */
@mixin flex-colum-spc {
  > * {
    display: block;
    margin: 0 auto;
  }
}

@mixin flex-pack-center {
  justify-content: center;
  -ms-flex-pack: center;
  -webkit-box-pack: center;
  -webkit-justify-content: center;
}

@mixin flex-pack-justify {
  justify-content: space-between;
  -webkit-justify-content: space-between;
}

@mixin flex-pack-around {
  justify-content: space-around;
  -webkit-justify-content: space-around;
}

@mixin main-bg {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  z-index: -1;
  overflow-y: auto;
}

@mixin main-bg-clause {
  position: fixed;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.70);
  display: flex;
  display: -webkit-flex;
  flex-direction: row;
  align-items: center;
  -webkit-align-items: center;
  top: 0;
  z-index: 999;
}

@mixin nav-title {
  font-size: 18px;
  color: #FFFFFF;
  letter-spacing: 0;
  margin-top: 28px;
  margin-left: 145px;
  display: inline-block;
  position: relative;
  z-index: 991;
}
